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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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Kenwood receiver no sound on FM source
Hi,
I have a strange problem on my Kenwood receiver. When I set the source to FM radio, I have no sound from the speakers anymore. When I set the source to AM, or to CD or TAPE I do have sound. So only FM is not working. It's a kenwood 4060. I opened the receiver, and checked all fuses but they tested ok. Any ideas of what to check? thanks |
#2
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Kenwood receiver no sound on FM source
All sorts of things... Bad selector switch. Broken leads. Bad FM front end.
Shorted FM IF transformer. |
#3
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Kenwood receiver no sound on FM source
Well,
FM does work as such. I receive channels, and the name of the channel and the currently aired song is displayed (thru rds). So it's only the sound output to the speakers that no longer works, and only for FM. It started when I tried to hook up 2 speakers per channel instead of one. On 18 feb, 15:29, "William Sommerwerck" wrote: All sorts of things... Bad selector switch. Broken leads. Bad FM front end. Shorted FM IF transformer. |
#4
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Kenwood receiver no sound on FM source
I do have a certain knowledge in pinball system board repair. So I
guess this is more or less the same. I have a dvm and a test probe. All other 'sources' like CD and AM radio sound very good. only fm sound output 'disappeared'. the sound stopped while connecting the second pair of speakers (in parallel) to the red and black speaker crimps. Thanks for any help Do you have any experience in troubleshooting/repair of home electronics? Do you have test equipment? You'll need a print, DVM and possibly a cheap scope to fix this one. |
#5
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Kenwood receiver no sound on FM source
Hmmm... I guess it will not be an easy fix then?
A print would be useful to track down where the audio signal stops. A high impedance audio test probe could probably be substituted for a scope. |
#6
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Kenwood receiver no sound on FM source
"OllieBommel" wrote in message ... Well, FM does work as such. I receive channels, and the name of the channel and the currently aired song is displayed (thru rds). So it's only the sound output to the speakers that no longer works, and only for FM. It started when I tried to hook up 2 speakers per channel instead of one. On 18 feb, 15:29, "William Sommerwerck" wrote: All sorts of things... Bad selector switch. Broken leads. Bad FM front end. Shorted FM IF transformer. Hooking up speakers would not cause the FM problem. Could have blown an amp channel, but then the other sources would not work. Maybe knocked off the antenna, or as someone else suggested, the current lack of FM could be a coincidence. Mark Z. |
#7
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Kenwood receiver no sound on FM source
Hit the FM stereo switch, set it to mono. Do you get any sound now?
When set to stereo the circuit is designed to mute any audio if the quality and strength of the signal being received is'nt stereo worthy ( better antenna/ orientation required). Your RDS is working , else i'd suspect FM detector transformer. Loading 2 pairs of speakers on would'nt cause this problem , as the rest have stated. Jango. |
#8
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Kenwood receiver no sound on FM source
Mark D. Zacharias wrote:
"OllieBommel" wrote in message ... Well, FM does work as such. I receive channels, and the name of the channel and the currently aired song is displayed (thru rds). So it's only the sound output to the speakers that no longer works, and only for FM. It started when I tried to hook up 2 speakers per channel instead of one. On 18 feb, 15:29, "William Sommerwerck" wrote: All sorts of things... Bad selector switch. Broken leads. Bad FM front end. Shorted FM IF transformer. Hooking up speakers would not cause the FM problem. Could have blown an amp channel, but then the other sources would not work. Maybe knocked off the antenna, or as someone else suggested, the current lack of FM could be a coincidence. Mark Z. That answer resonates with me, as well, OP. Go back and *carefully* check the antenna connection. If it looks good, unhook it anyway, and hook it up again. You'll have to do it anyway if you repair/replace the receiver, and it's a lot cheaper than those options. Also, the advice in the thread about switching the FM mode is sound. That might lead you to the same place; a bad antenna connection. jak |
#9
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Kenwood receiver no sound on FM source
Hi again,
I tested some more. Jango was right in that it has something to do with the fm signal being muted whenever it does not receive full stereo fm. The "stereo" on the display does not light. I once managed to quickly receive stereo and I heared the sound. But, I placed the receiver on different locations and it seems that I never can receive stereo fm for any length of time, which results in the muted sound. It's a kenwood KRA-4060 and I cannot find a "mono" button on the receiver or remote control to disable this "muting" behavior. I think there must be something broken on the FM receiver because it never receives in stereo, although it can always receive full RDS signal and a lot of different channels. I think when it can receive full RDS for a certain channel that the reception must be good enough to also receive stereo, not? Also the "tuned" light is on which indicates good reception. It auto-tunes to a lot of different channels. Only never in "stereo" and because it mutes the sound on mono, I have no sound at all. I tried a different antenna but still no luck. I really think the reception is good enough but somehow the "stereo reception" seems to be malfunctioning. I have a cheap small tower receiver as well on the same location and this does receive a stereo fm signal. It's stupid that it mutes all sound to the speaker when it does not receive stereo... Even more stupid is the fact that I cannot seem to change this behavior... The OP says the receiver is getting the RDS display of the channels and the current aired song.- Tekst uit oorspronkelijk bericht niet weergeven - - Tekst uit oorspronkelijk bericht weergeven - |
#10
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Kenwood receiver no sound on FM source
Meat Plow wrote:
On Tue, 19 Feb 2008 12:26:18 -0600, jakdedert wrote: Mark D. Zacharias wrote: "OllieBommel" wrote in message ... Well, FM does work as such. I receive channels, and the name of the channel and the currently aired song is displayed (thru rds). So it's only the sound output to the speakers that no longer works, and only for FM. It started when I tried to hook up 2 speakers per channel instead of one. On 18 feb, 15:29, "William Sommerwerck" wrote: All sorts of things... Bad selector switch. Broken leads. Bad FM front end. Shorted FM IF transformer. Hooking up speakers would not cause the FM problem. Could have blown an amp channel, but then the other sources would not work. Maybe knocked off the antenna, or as someone else suggested, the current lack of FM could be a coincidence. Mark Z. That answer resonates with me, as well, OP. Go back and *carefully* check the antenna connection. If it looks good, unhook it anyway, and hook it up again. You'll have to do it anyway if you repair/replace the receiver, and it's a lot cheaper than those options. Also, the advice in the thread about switching the FM mode is sound. That might lead you to the same place; a bad antenna connection. jak The OP says the receiver is getting the RDS display of the channels and the current aired song. Yeah, I know. What I don't know (don't have any receivers with this feature) is whether the signal threshold for RDS is higher, lower, or the same as for muting. In his latest post, he seems to be having issues with multiplex threshold as well...leading to antenna diagnosis again. jak |
#11
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Kenwood receiver no sound on FM source
OllieBommel wrote:
Hi again, I tested some more. Jango was right in that it has something to do with the fm signal being muted whenever it does not receive full stereo fm. The "stereo" on the display does not light. I once managed to quickly receive stereo and I heared the sound. But, I placed the receiver on different locations and it seems that I never can receive stereo fm for any length of time, which results in the muted sound. It's a kenwood KRA-4060 and I cannot find a "mono" button on the receiver or remote control to disable this "muting" behavior. I think there must be something broken on the FM receiver because it never receives in stereo, although it can always receive full RDS signal and a lot of different channels. I think when it can receive full RDS for a certain channel that the reception must be good enough to also receive stereo, not? Also the "tuned" light is on which indicates good reception. It auto-tunes to a lot of different channels. Only never in "stereo" and because it mutes the sound on mono, I have no sound at all. I tried a different antenna but still no luck. I really think the reception is good enough but somehow the "stereo reception" seems to be malfunctioning. I have a cheap small tower receiver as well on the same location and this does receive a stereo fm signal. It's stupid that it mutes all sound to the speaker when it does not receive stereo... Even more stupid is the fact that I cannot seem to change this behavior... The OP says the receiver is getting the RDS display of the channels and the current aired song.- Tekst uit oorspronkelijk bericht niet weergeven - - Tekst uit oorspronkelijk bericht weergeven - Ollie, can you look at the receiver and describe the antenna terminals? What is hooked to them? If nothing, that's *very* likely your problem. If 'something', disconnect it. Hook it up again and see if your problem still exhibits. It was working until you messed around back there. It's easy to knock something loose...which upon casual inspection still 'looks' good. In the case of no antenna at all, you may have only had very marginal reception in the first place (just above the muting threshold), and adding/moving wires took the signal level to just below that point. Check the antenna. jak |
#12
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Kenwood receiver no sound on FM source
"It started when I tried to hook up 2 speakers per channel instead of
one. " Do you think you might have shifted a tiny slider switch behind the unit , close to the speaker terminals?. Maybe thats where the mono stereo switch is located in this model. Jango. |
#13
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Kenwood receiver no sound on FM source
"Meat Plow" wrote in message ... On Tue, 19 Feb 2008 03:03:12 -0800, OllieBommel wrote: Hmmm... I guess it will not be an easy fix then? Easy is a conditional term. Easy for an experienced tech with basic test equipment. Not so easy for an inexperienced tech without a print. A print would be useful to track down where the audio signal stops. A high impedance audio test probe could probably be substituted for a scope. This is beginning to sound more like a discriminator alignment issue to me. Very common with digital tuners. A surround model might have the discriminator buried in a module, however... Mark Z. |
#14
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Kenwood receiver no sound on FM source
Well,
I previously only used this receiver for CD/Tape playback. I never used the antenna and FM tuner. I connected those T-shaped FM wire antenna's. Maybe these are not strong enough? Also, on the antenna input terminal there is written "75ohm". Does this need the antenna itself need to be 75ohm? Maybe these T-shaped wire antenna's are not 75 ohm? Check the antenna. jak- Tekst uit oorspronkelijk bericht niet weergeven - - Tekst uit oorspronkelijk bericht weergeven - |
#15
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Kenwood receiver no sound on FM source
"OllieBommel" wrote in message
... I previously only used this receiver for CD/Tape playback. I never used the antenna and FM tuner. I connected those T-shaped FM wire antennas. Maybe these are not strong enough? Also, on the antenna input terminal there is written "75ohm". Does this need the antenna itself need to be 75ohm? Maybe these T-shaped wire antenna's are not 75 ohm? Stupid question... Was the FM actually working before you tried to connect the extra speakers? That is, did you actually hear the FM playing? A T antenna is 300 ohms, not 75 ohms -- but that has nothing to do with your problem. In general, if any FM tuner is working, and you live in an area of reasonable signal strength, a foot or two of wire will pick up _something_. If you can't get _anything_ -- something is wrong with the tuner. If the display shows the RDS correctly for the station tuned in, then the antenna and at least part of the tuner are working. That means something "down the line" is kaput. |
#16
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Kenwood receiver no sound on FM source
Stupid question... Was the FM actually working before you tried to connect the extra speakers? That is, did you actually hear the FM playing? Yes, that's what confused me into thinking that something else was broken. For a short while, the receiver was playing with the antenna. But after a few minutes I tried to hook up the second pair of speakers to the same terminals and the moment I did that it suddenly stopped playing, as if some kind of fuse broke or some kind of protective circuitery jumped in. But for what I can read here (and I did not yet say this enough, but I do appreciate all the help you have given, folks!) , both fm and speaker connection would have nothing to do with each other... Well, I think I must accept the fact that indeed something "down the line" is broken and perhaps it's time to get it replaced with another tuner. |
#17
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Kenwood receiver no sound on FM source
Stupid question... Was the FM actually working before you tried to
connect the extra speakers? That is, did you actually hear the FM playing? Yes, that's what confused me into thinking that something else was broken. For a short while, the receiver was playing with the antenna. But after a few minutes I tried to hook up the second pair of speakers to the same terminals and the moment I did that it suddenly stopped playing, as if some kind of fuse broke or some kind of protective circuitery jumped in. But for what I can read here (and I did not yet say this enough, but I do appreciate all the help you have given, folks!) , both fm and speaker connection would have nothing to do with each other... Well, I think I must accept the fact that indeed something "down the line" is broken and perhaps it's time to get it replaced with another tuner. Let me throw a little Latin at you: "Post hoc, ergo procter hoct". This is a fallacy in reasoning that means "It followed, therefore it was caused by." Barring some Truly Weird behavior in the receiver, this is coincidence. You need to take the unit to someone who can properly signal-trace the tuner and amplifier, and find the source of the problem. |
#18
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Kenwood receiver no sound on FM source
OllieBommel wrote:
Stupid question... Was the FM actually working before you tried to connect the extra speakers? That is, did you actually hear the FM playing? Yes, that's what confused me into thinking that something else was broken. For a short while, the receiver was playing with the antenna. WHAT ANTENNA? But after a few minutes I tried to hook up the second pair of speakers to the same terminals and the moment I did that it suddenly stopped playing, as if some kind of fuse broke or some kind of protective circuitery jumped in. Could be that the muting threshold was reached. But for what I can read here (and I did not yet say this enough, but I do appreciate all the help you have given, folks!) , both fm and speaker connection would have nothing to do with each other... Correct, but you could have done something else while you were back there. CHECK THE ANTENNA CONNECTIONS! I've posted this a couple of times, but you only seem to respond to people who support your fixation that something must be broken. Well, I think I must accept the fact that indeed something "down the line" is broken and perhaps it's time to get it replaced with another tuner. Ollie, I can't seem to emphasize this enough. EXCUSE ME FOR SHOUTING, BUT HOOK UP AN ANTENNA OF SOME SORT! You seem to be saying that nothing is connected to the terminals. If nothing is connected to the antenna terminals there is NO ANTENNA! In strong signal areas, a receiver may pick up 'some' signal without one; but it will be tentative. At the threshold, almost anything, like *moving some unrelated wires* in the vicinity, could take the signal below that threshold. Lack of stereo indication on some stations indicates you are near that threshold. You need some sort of antenna. HOOK UP AN ANTENNA. It may not help, but it's a lot cheaper than replacing the receiver--especially if that one doesn't work any either, because you didn't HOOK UP AN ANTENNA. Your new receiver will need one, anyway. It may pick up 'something' without one, but reception will be cleaner, clearer and more reliable if you USE AN ANTENNA. Report back. jak |
#19
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Kenwood receiver no sound on FM source
On 21 feb, 19:04, jakdedert wrote:
OllieBommel wrote: Stupid question... Was the FM actually working before you tried to connect the extra speakers? That is, did you actually hear the FM playing? Yes, that's what confused me into thinking that something else was broken. For a short while, the receiver was playing with the antenna. WHAT ANTENNA? Hi Jak, I replied to other guys as well, mentioning that I did connect an antenna, namely a T-shaped wire antenna. William even replied to this that it is a 300ohm instead of a 75ohm. Maybe you missed this post. Because it's a lengthy thread by now This antenna does receive 'some' signal but nearly not enough to get past the muting threshold, or to receive a stereo signal. I will try a more powerfull antenna, maybe with a build-in amplifier of some kind. But I'm going to have to buy this. Maybe this will give a signal strong enough to get something out of the receiver. Well, these digital receivers do seem to need a much stronger antenna than the old analogue receivers because with such an older one I can manually tune in channels and receive stereo. Anyway. thanks all for your help, you too Jak. |
#20
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Kenwood receiver no sound on FM source
"OllieBommel" wrote in message
... On 21 feb, 19:04, jakdedert wrote: OllieBommel wrote: Stupid question... Was the FM actually working before you tried to connect the extra speakers? That is, did you actually hear the FM playing? Yes, that's what confused me into thinking that something else was broken. For a short while, the receiver was playing with the antenna. WHAT ANTENNA? Hi Jak, I replied to other guys as well, mentioning that I did connect an antenna, namely a T-shaped wire antenna. William even replied to this that it is a 300ohm instead of a 75ohm. Maybe you missed this post. Because it's a lengthy thread by now This antenna does receive 'some' signal but nearly not enough to get past the muting threshold, or to receive a stereo signal. I will try a more powerfull antenna, maybe with a build-in amplifier of some kind. But I'm going to have to buy this. Maybe this will give a signal strong enough to get something out of the receiver. Well, these digital receivers do seem to need a much stronger antenna than the old analogue receivers because with such an older one I can manually tune in channels and receive stereo. Anyway. thanks all for your help, you too Jak. But the point is that you say the tuner DID work -- that is, it received at least one station well -- at one time. Therefore, the antenna, per se, is not the problem. When you had reception, what antenna was connected to the unit? Digital receivers DO NOT require a stronger signal level. |
#21
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Kenwood receiver no sound on FM source
On Feb 18, 4:04*am, OllieBommel wrote:
Hi, I have a strange problem on my Kenwood receiver. When I set the source to FM radio, I have no sound from the speakers anymore. When I set the source to AM, or to CD or TAPE I do have sound. So only FM is not working. It's a kenwood 4060. I opened the receiver, and checked all fuses but they tested ok. Any ideas of what to check? thanks Best Buy for a new one |
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